1. Field of the Invention
Medical technology has advanced dramatically and swiftly over the past decades. The advances have been particularly significant within the fields of genetic engineering, cell technology, and in their proposed uses in actual therapies. For example, it is an increasingly common proposed medical technique to inject live cells into the human body. The intention of these cell implantation therapies (with genetically engineered cells or harvested cells) is to have the implanted cells attach to or settle into the tissues and provide their essential functions in their new location. The function of these therapeutic techniques may be to repair a genetic defect (producing a needed substance that the body is failing to create), repair traumatic damage, replace disease-diminished cells, contribute to the mechanical properties of an organ by the structures they build, and so forth. The science of cell implantation therapy is far in advance of the engineering technology needed to implement these therapies.
One engineering problem that is considered here is an appreciation of the fact that not all cells survive the injection process. When a substantial fraction of the cells fails to settle and function in the body, the efficacy of the treatment is much reduced. Although some cell deterioration is expected, there has been almost no consideration in the literature of this problem. There has been little publication on the design and engineering of delivery systems to reduce the impact of the delivery system on aggravating normal loss of viable cells.
Cells to be used for implantation are often grown on a substrate, rather than floating freely in nutrient. If this process fails, there are no cells to harvest, and treatment cannot be attempted on a patient. Where treatment fails to establish cells in the body, their survival may have been hampered in one or more of the stages of harvest (detaching them from the substrate and creating an injectable suspension), storage, transport within the system, injection, and motion through tissue before reattaching themselves. (If attached cells fail to survive or function as intended, the problems are most likely specific to the bioengineering of the particular cell line, and we do not address that problem here.)
U.S. Pat. No. 5,997,525 describes a system for delivering therapeutic or diagnostic agents to the heart, including a catheter that delivers the material to be delivered in a viscous carrier. The material may be delivered in association with an elongated, flexible transmission means for lasing that forms channels in the heart wall, as delivery locations.
U.S. Pat. No. 5,993,462 describes a shapeable catheter, which may include a pre-shaped region bent into a predetermined shape. A lumen may be proportioned to slidably receive a core wire. A pull wire may be provided to allow the user to cause deflection at a distal portion of the catheter.
U.S. Pat. No. 5,980,885 describes a method for inducing in vivo proliferation of precursor cells located in mammalian neural tissue. Simple glass pipettes are used to deliver the cell suspensions at levels of about 50,000 cell/microliter.
As can be seen from this review of the prior art, the delivery systems described tend to be essentially primitive tubes, with no consideration of flow functions or physical effects on cells during the delivery process. To assure that cell implantation becomes a viable procedure, it is essential that engineering considerations be used in the design of the pick-up, transportation and cell delivery devices.
Pick-up, transport and delivery systems for cell therapy and implantation procedures are designed and conceptual planning parameters are provided intended to increase the survival rate of cells used during these procedures. The systems provide various movement effecting systems that minimize stress on cells, which stress might damage cells, reduce their survivability, and/or reduce their ability to attach upon delivery. Such systems include, peristalsis flow, bolus flow, gradated (sloped) size exit ports, and other systems that reduce vortices, compressive effects, cell blocking effects, and other stresses.